The present invention relates to an automatic warning system for trailer hitches and, in particular, to an audible warning system which signals the driver of an automobile when the hitch becomes loose or uncoupled and an alarm system which can be used to provide an automatic warning against unauthorized uncoupling of hitched trailer vehicles or attempts to disengage or short-out the alarm circuit. Trailers are conventionally hitched to towing vehicles using a ball and socket hitch-type arrangement. The ball is included as part of an automobile hitch mount secured to the rear of the automobile and cooperates with a cup-shaped coupling member or socket attached to the trailer. A coupling or clamping means secures the socket to the ball while providing maneuverability between the trailer and the towing vehicle. Such coupling devices presently in use on the highways present a potential hazard because of the tendency of the socket to become loose from the trailer ball due to improper coupling or because of rough traveling conditions. Failure of the coupling can result in tragic accidents causing severe injury or death and damage to personal property. Normally, the driver of the vehicle is unaware that the coupling is loose until the coupling actually separates.
Attempts have been made to provide safety features for two vehicles that are hitched by using ball-type couplers having coupler locks and/or chains, but even these are not entirely satisfactory or safe. One example of a visual warning system when an automobile trailer hitch becomes loose is described in Quilici et al. U.S. Pat. No. 3,710,370.
With this background in mind, it is an object of the present invention to provide a warning system for trailer hitches that will provide a signal to the automobile driver when the trailer hitch coupling becomes loose in order that the driver can slow down and pull off the side of the road to check the trouble initiated by the advance warning given before the coupling separates from the ball.
Another object of the present invention is the provision of a dual warning system for trailer hitches in which an audible and/or visible warning is provided when an attempt is made to uncouple the trailer hitch by unauthorized personnel or to disengage the warning system from the automobile battery.
Still another object of the present invention is to provide a dual warning system which is simple in operation and combines both functions of warning of loose ball couplings and unauthorized uncouplings and attempts to disengage the warning system within a compact electronic package.
The present invention provides a warning system for automobile trailer hitches and couplers having a hitch ball with a switch built therein whereby loosening of the coupler from the hitch ball causes actuation of a relay circuit which in turn provides a visual and/or audible alarm signal. The warning system also includes an anti-tampering circuit which provides a visual or audible signal if an attempt to de-energize the circuit is made. The switch may be a pushbutton, toggle snap switch or a magnetic switch which is activated by the coupler resting on the hitch ball in its normal operation position. Preferably, the alarm signal is provided by the vehicle battery and horn which are connected through suitable circuits to the ball switch.